1 /* Structure for saving state for a nested function.
2 Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
23 #if !defined(NULL_TREE) && !defined(tree)
24 typedef union union_node
*_function_tree
;
25 #define tree _function_tree
27 #if !defined(NULL_RTX) && !defined(rtx)
28 typedef struct rtx_def
*_function_rtx
;
29 #define rtx _function_rtx
35 enum machine_mode promoted_mode
;
37 struct var_refs_queue
*next
;
40 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
41 Each element describes one pending sequence.
42 The main insn-chain is saved in the last element of the chain,
43 unless the chain is empty. */
47 /* First and last insns in the chain of the saved sequence. */
49 tree sequence_rtl_expr
;
50 struct sequence_stack
*next
;
53 extern struct sequence_stack
*sequence_stack
;
55 /* Stack of single obstacks. */
57 struct simple_obstack_stack
59 struct obstack
*obstack
;
60 struct simple_obstack_stack
*next
;
65 /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
66 After rtl generation, it is 1 plus the largest register number used. */
69 /* Lowest label number in current function. */
70 int x_first_label_num
;
72 /* The ends of the doubly-linked chain of rtl for the current function.
73 Both are reset to null at the start of rtl generation for the function.
75 start_sequence saves both of these on `sequence_stack' along with
76 `sequence_rtl_expr' and then starts a new, nested sequence of insns. */
80 /* RTL_EXPR within which the current sequence will be placed. Use to
81 prevent reuse of any temporaries within the sequence until after the
82 RTL_EXPR is emitted. */
83 tree sequence_rtl_expr
;
85 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
86 Each element describes one pending sequence.
87 The main insn-chain is saved in the last element of the chain,
88 unless the chain is empty. */
89 struct sequence_stack
*sequence_stack
;
91 /* INSN_UID for next insn emitted.
92 Reset to 1 for each function compiled. */
95 /* Line number and source file of the last line-number NOTE emitted.
96 This is used to avoid generating duplicates. */
98 const char *x_last_filename
;
100 /* A vector indexed by pseudo reg number. The allocated length
101 of this vector is regno_pointer_flag_length. Since this
102 vector is needed during the expansion phase when the total
103 number of registers in the function is not yet known,
104 it is copied and made bigger when necessary. */
105 char *regno_pointer_flag
;
106 int regno_pointer_flag_length
;
108 /* Indexed by pseudo register number, if nonzero gives the known alignment
109 for that pseudo (if regno_pointer_flag is set).
110 Allocated in parallel with regno_pointer_flag. */
111 char *regno_pointer_align
;
113 /* Indexed by pseudo register number, gives the rtx for that pseudo.
114 Allocated in parallel with regno_pointer_flag. */
115 rtx
*x_regno_reg_rtx
;
118 /* For backward compatibility... eventually these should all go away. */
119 #define reg_rtx_no (cfun->emit->x_reg_rtx_no)
120 #define seq_rtl_expr (cfun->emit->sequence_rtl_expr)
121 #define regno_reg_rtx (cfun->emit->x_regno_reg_rtx)
122 #define seq_stack (cfun->emit->sequence_stack)
124 #define REGNO_POINTER_ALIGN(REGNO) (cfun->emit->regno_pointer_align[REGNO])
125 #define REGNO_POINTER_FLAG(REGNO) (cfun->emit->regno_pointer_flag[REGNO])
129 /* Number of units that we should eventually pop off the stack.
130 These are the arguments to function calls that have already returned. */
131 int x_pending_stack_adjust
;
133 /* Number of units that we should eventually pop off the stack.
134 These are the arguments to function calls that have not happened yet. */
135 int x_arg_space_so_far
;
137 /* Under some ABIs, it is the caller's responsibility to pop arguments
138 pushed for function calls. A naive implementation would simply pop
139 the arguments immediately after each call. However, if several
140 function calls are made in a row, it is typically cheaper to pop
141 all the arguments after all of the calls are complete since a
142 single pop instruction can be used. Therefore, GCC attempts to
143 defer popping the arguments until absolutely necessary. (For
144 example, at the end of a conditional, the arguments must be popped,
145 since code outside the conditional won't know whether or not the
146 arguments need to be popped.)
148 When INHIBIT_DEFER_POP is non-zero, however, the compiler does not
149 attempt to defer pops. Instead, the stack is popped immediately
150 after each call. Rather then setting this variable directly, use
151 NO_DEFER_POP and OK_DEFER_POP. */
152 int x_inhibit_defer_pop
;
154 /* Nonzero means __builtin_saveregs has already been done in this function.
155 The value is the pseudoreg containing the value __builtin_saveregs
157 rtx x_saveregs_value
;
159 /* Similarly for __builtin_apply_args. */
160 rtx x_apply_args_value
;
162 /* List of labels that must never be deleted. */
165 /* Postincrements that still need to be expanded. */
169 #define pending_stack_adjust (cfun->expr->x_pending_stack_adjust)
170 #define arg_space_so_far (cfun->expr->x_arg_space_so_far)
171 #define inhibit_defer_pop (cfun->expr->x_inhibit_defer_pop)
172 #define saveregs_value (cfun->expr->x_saveregs_value)
173 #define apply_args_value (cfun->expr->x_apply_args_value)
174 #define forced_labels (cfun->expr->x_forced_labels)
175 #define pending_chain (cfun->expr->x_pending_chain)
177 /* This structure can save all the important global and static variables
178 describing the status of the current function. */
182 struct function
*next_global
;
183 struct function
*next
;
185 struct eh_status
*eh
;
186 struct stmt_status
*stmt
;
187 struct expr_status
*expr
;
188 struct emit_status
*emit
;
189 struct varasm_status
*varasm
;
191 /* For function.c. */
193 /* Name of this function. */
195 /* Points to the FUNCTION_DECL of this function. */
198 /* Number of bytes of args popped by function being compiled on its return.
199 Zero if no bytes are to be popped.
200 May affect compilation of return insn or of function epilogue. */
203 /* Nonzero if function being compiled needs to be given an address
204 where the value should be stored. */
207 /* Nonzero if function being compiled needs to
208 return the address of where it has put a structure value. */
209 int returns_pcc_struct
;
211 /* Nonzero if the current function returns a pointer type. */
214 /* Nonzero if function being compiled needs to be passed a static chain. */
217 /* Nonzero if function being compiled can call setjmp. */
220 /* Nonzero if function being compiled can call longjmp. */
223 /* Nonzero if function being compiled can call alloca,
224 either as a subroutine or builtin. */
227 /* Nonzero if function being compiled receives nonlocal gotos
228 from nested functions. */
230 int has_nonlocal_label
;
232 /* Nonzero if function being compiled has nonlocal gotos to parent
234 int has_nonlocal_goto
;
236 /* Nonzero if function being compiled contains nested functions. */
237 int contains_functions
;
239 /* Nonzero if the function being compiled issues a computed jump. */
240 int has_computed_jump
;
242 /* Nonzero if the current function is a thunk (a lightweight function that
243 just adjusts one of its arguments and forwards to another function), so
244 we should try to cut corners where we can. */
247 /* If function's args have a fixed size, this is that size, in bytes.
249 May affect compilation of return insn or of function epilogue. */
252 /* # bytes the prologue should push and pretend that the caller pushed them.
253 The prologue must do this, but only if parms can be passed in
255 int pretend_args_size
;
257 /* # of bytes of outgoing arguments. If ACCUMULATE_OUTGOING_ARGS is
258 defined, the needed space is pushed by the prologue. */
259 int outgoing_args_size
;
261 /* This is the offset from the arg pointer to the place where the first
262 anonymous arg can be found, if there is one. */
265 /* Nonzero if current function uses varargs.h or equivalent.
266 Zero for functions that use stdarg.h. */
269 /* Nonzero if current function uses stdarg.h or equivalent.
270 Zero for functions that use varargs.h. */
273 /* Quantities of various kinds of registers
274 used for the current function's args. */
275 CUMULATIVE_ARGS args_info
;
277 /* If non-zero, an RTL expression for the location at which the current
278 function returns its result. If the current function returns its
279 result in a register, current_function_return_rtx will always be
280 the hard register containing the result. */
283 /* The arg pointer hard register, or the pseudo into which it was copied. */
284 rtx internal_arg_pointer
;
286 /* Language-specific reason why the current function cannot be made
288 const char *cannot_inline
;
290 /* Nonzero if instrumentation calls for function entry and exit should be
292 int instrument_entry_exit
;
294 /* Nonzero if memory access checking be enabled in the current function. */
295 int check_memory_usage
;
297 /* Nonzero if stack limit checking should be enabled in the current
301 /* Number of function calls seen so far in current function. */
302 int x_function_call_count
;
304 /* Nonzero if this function is being processed in function-at-a-time
305 mode. In other words, if all tree structure for this function,
306 including the BLOCK tree, is created before RTL generation
308 int x_whole_function_mode_p
;
310 /* Nonzero if the back-end should not keep track of expressions that
311 determine the size of variable-sized objects. Normally, such
312 expressions are saved away, and then expanded when the next
313 function is started. For example, if a parameter has a
314 variable-sized type, then the size of the parameter is computed
315 when the function body is entered. However, some front-ends do
316 not desire this behavior. */
317 int x_dont_save_pending_sizes_p
;
319 /* List (chain of TREE_LIST) of LABEL_DECLs for all nonlocal labels
320 (labels to which there can be nonlocal gotos from nested functions)
322 tree x_nonlocal_labels
;
324 /* List (chain of EXPR_LIST) of stack slots that hold the current handlers
325 for nonlocal gotos. There is one for every nonlocal label in the
326 function; this list matches the one in nonlocal_labels.
327 Zero when function does not have nonlocal labels. */
328 rtx x_nonlocal_goto_handler_slots
;
330 /* List (chain of EXPR_LIST) of labels heading the current handlers for
332 rtx x_nonlocal_goto_handler_labels
;
334 /* RTX for stack slot that holds the stack pointer value to restore
336 Zero when function does not have nonlocal labels. */
337 rtx x_nonlocal_goto_stack_level
;
339 /* Label that will go on parm cleanup code, if any.
340 Jumping to this label runs cleanup code for parameters, if
341 such code must be run. Following this code is the logical return
345 /* Label that will go on function epilogue.
346 Jumping to this label serves as a "return" instruction
347 on machines which require execution of the epilogue on all returns. */
350 /* List (chain of EXPR_LISTs) of pseudo-regs of SAVE_EXPRs.
351 So we can mark them all live at the end of the function, if nonopt. */
352 rtx x_save_expr_regs
;
354 /* List (chain of EXPR_LISTs) of all stack slots in this function.
355 Made for the sake of unshare_all_rtl. */
356 rtx x_stack_slot_list
;
358 /* Chain of all RTL_EXPRs that have insns in them. */
359 tree x_rtl_expr_chain
;
361 /* Label to jump back to for tail recursion, or 0 if we have
362 not yet needed one for this function. */
363 rtx x_tail_recursion_label
;
365 /* Place after which to insert the tail_recursion_label if we need one. */
366 rtx x_tail_recursion_reentry
;
368 /* Location at which to save the argument pointer if it will need to be
369 referenced. There are two cases where this is done: if nonlocal gotos
370 exist, or if vars stored at an offset from the argument pointer will be
371 needed by inner routines. */
372 rtx x_arg_pointer_save_area
;
374 /* Offset to end of allocated area of stack frame.
375 If stack grows down, this is the address of the last stack slot allocated.
376 If stack grows up, this is the address for the next slot. */
377 HOST_WIDE_INT x_frame_offset
;
379 /* List (chain of TREE_LISTs) of static chains for containing functions.
380 Each link has a FUNCTION_DECL in the TREE_PURPOSE and a reg rtx
381 in an RTL_EXPR in the TREE_VALUE. */
382 tree x_context_display
;
384 /* List (chain of TREE_LISTs) of trampolines for nested functions.
385 The trampoline sets up the static chain and jumps to the function.
386 We supply the trampoline's address when the function's address is
389 Each link has a FUNCTION_DECL in the TREE_PURPOSE and a reg rtx
390 in an RTL_EXPR in the TREE_VALUE. */
391 tree x_trampoline_list
;
393 /* Insn after which register parms and SAVE_EXPRs are born, if nonopt. */
394 rtx x_parm_birth_insn
;
396 /* Last insn of those whose job was to put parms into their nominal
398 rtx x_last_parm_insn
;
400 /* 1 + last pseudo register number possibly used for loading a copy
401 of a parameter of this function. */
404 /* Vector indexed by REGNO, containing location on stack in which
405 to put the parm which is nominally in pseudo register REGNO,
406 if we discover that that parm must go in the stack. The highest
407 element in this vector is one less than MAX_PARM_REG, above. */
408 rtx
*x_parm_reg_stack_loc
;
410 /* List of all temporaries allocated, both available and in use. */
411 struct temp_slot
*x_temp_slots
;
413 /* Current nesting level for temporaries. */
414 int x_temp_slot_level
;
416 /* Current nesting level for variables in a block. */
417 int x_var_temp_slot_level
;
419 /* When temporaries are created by TARGET_EXPRs, they are created at
420 this level of temp_slot_level, so that they can remain allocated
421 until no longer needed. CLEANUP_POINT_EXPRs define the lifetime
423 int x_target_temp_slot_level
;
425 /* This slot is initialized as 0 and is added to
426 during the nested function. */
427 struct var_refs_queue
*fixup_var_refs_queue
;
430 int all_types_permanent
;
431 struct momentary_level
*momentary_stack
;
432 char *maybepermanent_firstobj
;
433 char *temporary_firstobj
;
434 char *momentary_firstobj
;
435 char *momentary_function_firstobj
;
436 struct obstack
*current_obstack
;
437 struct obstack
*function_obstack
;
438 struct obstack
*function_maybepermanent_obstack
;
439 struct obstack
*expression_obstack
;
440 struct obstack
*saveable_obstack
;
441 struct obstack
*rtl_obstack
;
443 /* For integrate.c. */
445 /* This is in fact an rtvec. */
446 void *original_arg_vector
;
447 tree original_decl_initial
;
448 /* Last insn of those whose job was to put parms into their nominal
450 rtx inl_last_parm_insn
;
451 /* Highest label number in current function. */
452 int inl_max_label_num
;
454 /* Nonzero if the current function uses the constant pool. */
459 /* Nonzero if the current function uses pic_offset_table_rtx. */
460 int uses_pic_offset_table
;
461 /* tm.h can use this to store whatever it likes. */
462 struct machine_function
*machine
;
463 /* The largest alignment of slot allocated on the stack. */
464 int stack_alignment_needed
;
465 /* Preferred alignment of the end of stack frame. */
466 int preferred_stack_boundary
;
468 /* Language-specific code can use this to store whatever it likes. */
469 struct language_function
*language
;
473 /* If some insns can be deferred to the delay slots of the epilogue, the
474 delay list for them is recorded here. */
475 rtx epilogue_delay_list
;
478 /* The function currently being compiled. */
479 extern struct function
*cfun
;
481 /* A list of all functions we have compiled so far. */
482 extern struct function
*all_functions
;
484 /* For backward compatibility... eventually these should all go away. */
485 #define current_function_name (cfun->name)
486 #define current_function_pops_args (cfun->pops_args)
487 #define current_function_returns_struct (cfun->returns_struct)
488 #define current_function_returns_pcc_struct (cfun->returns_pcc_struct)
489 #define current_function_returns_pointer (cfun->returns_pointer)
490 #define current_function_needs_context (cfun->needs_context)
491 #define current_function_calls_setjmp (cfun->calls_setjmp)
492 #define current_function_calls_alloca (cfun->calls_alloca)
493 #define current_function_calls_longjmp (cfun->calls_longjmp)
494 #define current_function_has_computed_jump (cfun->has_computed_jump)
495 #define current_function_contains_functions (cfun->contains_functions)
496 #define current_function_is_thunk (cfun->is_thunk)
497 #define current_function_args_info (cfun->args_info)
498 #define current_function_args_size (cfun->args_size)
499 #define current_function_pretend_args_size (cfun->pretend_args_size)
500 #define current_function_outgoing_args_size (cfun->outgoing_args_size)
501 #define current_function_arg_offset_rtx (cfun->arg_offset_rtx)
502 #define current_function_varargs (cfun->varargs)
503 #define current_function_stdarg (cfun->stdarg)
504 #define current_function_internal_arg_pointer (cfun->internal_arg_pointer)
505 #define current_function_return_rtx (cfun->return_rtx)
506 #define current_function_instrument_entry_exit (cfun->instrument_entry_exit)
507 #define current_function_check_memory_usage (cfun->check_memory_usage)
508 #define current_function_limit_stack (cfun->limit_stack)
509 #define current_function_uses_pic_offset_table (cfun->uses_pic_offset_table)
510 #define current_function_uses_const_pool (cfun->uses_const_pool)
511 #define current_function_cannot_inline (cfun->cannot_inline)
512 #define current_function_epilogue_delay_list (cfun->epilogue_delay_list)
513 #define current_function_has_nonlocal_label (cfun->has_nonlocal_label)
514 #define current_function_has_nonlocal_goto (cfun->has_nonlocal_goto)
516 #define max_parm_reg (cfun->x_max_parm_reg)
517 #define parm_reg_stack_loc (cfun->x_parm_reg_stack_loc)
518 #define cleanup_label (cfun->x_cleanup_label)
519 #define return_label (cfun->x_return_label)
520 #define save_expr_regs (cfun->x_save_expr_regs)
521 #define stack_slot_list (cfun->x_stack_slot_list)
522 #define parm_birth_insn (cfun->x_parm_birth_insn)
523 #define frame_offset (cfun->x_frame_offset)
524 #define tail_recursion_label (cfun->x_tail_recursion_label)
525 #define tail_recursion_reentry (cfun->x_tail_recursion_reentry)
526 #define arg_pointer_save_area (cfun->x_arg_pointer_save_area)
527 #define rtl_expr_chain (cfun->x_rtl_expr_chain)
528 #define last_parm_insn (cfun->x_last_parm_insn)
529 #define context_display (cfun->x_context_display)
530 #define trampoline_list (cfun->x_trampoline_list)
531 #define function_call_count (cfun->x_function_call_count)
532 #define temp_slots (cfun->x_temp_slots)
533 #define temp_slot_level (cfun->x_temp_slot_level)
534 #define target_temp_slot_level (cfun->x_target_temp_slot_level)
535 #define var_temp_slot_level (cfun->x_var_temp_slot_level)
536 #define nonlocal_labels (cfun->x_nonlocal_labels)
537 #define nonlocal_goto_handler_slots (cfun->x_nonlocal_goto_handler_slots)
538 #define nonlocal_goto_handler_labels (cfun->x_nonlocal_goto_handler_labels)
539 #define nonlocal_goto_stack_level (cfun->x_nonlocal_goto_stack_level)
541 /* The FUNCTION_DECL for an inline function currently being expanded. */
542 extern tree inline_function_decl
;
544 /* Given a function decl for a containing function,
545 return the `struct function' for it. */
546 struct function
*find_function_data
PARAMS ((tree
));
548 /* Pointer to chain of `struct function' for containing functions. */
549 extern struct function
*outer_function_chain
;
551 /* Set NOTE_BLOCK for each block note in the current function. */
552 extern void identify_blocks
PARAMS ((void));
554 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
555 and create duplicate blocks. */
556 extern void reorder_blocks
PARAMS ((void));
558 /* Set BLOCK_NUMBER for all the blocks in FN. */
559 extern void number_blocks
PARAMS ((tree
));
561 /* Return size needed for stack frame based on slots so far allocated.
562 This size counts from zero. It is not rounded to STACK_BOUNDARY;
563 the caller may have to do that. */
564 extern HOST_WIDE_INT get_frame_size
PARAMS ((void));
565 /* Likewise, but for a different than the current function. */
566 extern HOST_WIDE_INT get_func_frame_size
PARAMS ((struct function
*));
568 /* These variables hold pointers to functions to
569 save and restore machine-specific data,
570 in push_function_context and pop_function_context. */
571 extern void (*init_machine_status
) PARAMS ((struct function
*));
572 extern void (*mark_machine_status
) PARAMS ((struct function
*));
573 extern void (*save_machine_status
) PARAMS ((struct function
*));
574 extern void (*restore_machine_status
) PARAMS ((struct function
*));
575 extern void (*free_machine_status
) PARAMS ((struct function
*));
577 /* Likewise, but for language-specific data. */
578 extern void (*init_lang_status
) PARAMS ((struct function
*));
579 extern void (*mark_lang_status
) PARAMS ((struct function
*));
580 extern void (*save_lang_status
) PARAMS ((struct function
*));
581 extern void (*restore_lang_status
) PARAMS ((struct function
*));
582 extern void (*free_lang_status
) PARAMS ((struct function
*));
584 /* Save and restore status information for a nested function. */
585 extern void save_tree_status
PARAMS ((struct function
*));
586 extern void restore_tree_status
PARAMS ((struct function
*));
587 extern void restore_emit_status
PARAMS ((struct function
*));
588 extern void free_after_parsing
PARAMS ((struct function
*));
589 extern void free_after_compilation
PARAMS ((struct function
*));
591 extern void init_varasm_status
PARAMS ((struct function
*));
592 extern void free_varasm_status
PARAMS ((struct function
*));
593 extern void free_emit_status
PARAMS ((struct function
*));
594 extern void free_stmt_status
PARAMS ((struct function
*));
595 extern void free_eh_status
PARAMS ((struct function
*));
596 extern void free_expr_status
PARAMS ((struct function
*));
598 extern rtx get_first_block_beg
PARAMS ((void));
601 extern void diddle_return_value
PARAMS ((void (*)(rtx
, void*), void*));
602 extern void clobber_return_register
PARAMS ((void));
603 extern void use_return_register
PARAMS ((void));
606 extern void init_virtual_regs
PARAMS ((struct emit_status
*));
608 /* Called once, at initialization, to initialize function.c. */
609 extern void init_function_once
PARAMS ((void));